// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_BASE_MODELS_TREE_MODEL_H_
#define UI_BASE_MODELS_TREE_MODEL_H_

#include <vector>

#include "base/strings/string16.h"
#include "ui/base/ui_base_export.h"

namespace gfx {
class ImageSkia;
}

namespace ui {

class TreeModel;

// TreeModelNode --------------------------------------------------------------

// Type of class returned from the model.
class TreeModelNode {
public:
    // Returns the title for the node.
    virtual const base::string16& GetTitle() const = 0;

protected:
    virtual ~TreeModelNode() { }
};

// Observer for the TreeModel. Notified of significant events to the model.
class UI_BASE_EXPORT TreeModelObserver {
public:
    // Notification that nodes were added to the specified parent.
    virtual void TreeNodesAdded(TreeModel* model,
        TreeModelNode* parent,
        int start,
        int count)
        = 0;

    // Notification that nodes were removed from the specified parent.
    virtual void TreeNodesRemoved(TreeModel* model,
        TreeModelNode* parent,
        int start,
        int count)
        = 0;

    // Notification that the contents of a node has changed.
    virtual void TreeNodeChanged(TreeModel* model, TreeModelNode* node) = 0;

protected:
    virtual ~TreeModelObserver() { }
};

// TreeModel ------------------------------------------------------------------

// The model for TreeView.
class UI_BASE_EXPORT TreeModel {
public:
    // Returns the root of the tree. This may or may not be shown in the tree,
    // see SetRootShown for details.
    virtual TreeModelNode* GetRoot() = 0;

    // Returns the number of children in |parent|.
    virtual int GetChildCount(TreeModelNode* parent) = 0;

    // Returns the child node of |parent| at |index|.
    virtual TreeModelNode* GetChild(TreeModelNode* parent, int index) = 0;

    // Returns the index of |child| in |parent|.
    virtual int GetIndexOf(TreeModelNode* parent, TreeModelNode* child) = 0;

    // Returns the parent of |node|, or NULL if |node| is the root.
    virtual TreeModelNode* GetParent(TreeModelNode* node) = 0;

    // Adds an observer of the model.
    virtual void AddObserver(TreeModelObserver* observer) = 0;

    // Removes an observer of the model.
    virtual void RemoveObserver(TreeModelObserver* observer) = 0;

    // Sets the title of |node|.
    // This is only invoked if the node is editable and the user edits a node.
    virtual void SetTitle(TreeModelNode* node, const base::string16& title);

    // Returns the set of icons for the nodes in the tree. You only need override
    // this if you don't want to use the default folder icons.
    virtual void GetIcons(std::vector<gfx::ImageSkia>* icons) { }

    // Returns the index of the icon to use for |node|. Return -1 to use the
    // default icon. The index is relative to the list of icons returned from
    // GetIcons.
    virtual int GetIconIndex(TreeModelNode* node);

protected:
    virtual ~TreeModel() { }
};

} // namespace ui

#endif // UI_BASE_MODELS_TREE_MODEL_H_
